U.S. patent application number 16/267510 was filed with the patent office on 2019-08-08 for post processing arrangement for shaped bodies manufactured additively by photopolymerization.
The applicant listed for this patent is Ivoclar Vivadent AG. Invention is credited to John HENDRIK.
Application Number | 20190240924 16/267510 |
Document ID | / |
Family ID | 61167988 |
Filed Date | 2019-08-08 |
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United States Patent
Application |
20190240924 |
Kind Code |
A1 |
HENDRIK; John |
August 8, 2019 |
POST PROCESSING ARRANGEMENT FOR SHAPED BODIES MANUFACTURED
ADDITIVELY BY PHOTOPOLYMERIZATION
Abstract
The present invention relates to a post processing arrangement
for shaped bodies manufactured additively by photopolymerization,
which has a cleaning station for cleaning and a finishing station
for post-exposure of the shaped body, characterized in that the
cleaning station and the finishing station are housed in a housing
(2), capable of standing on a horizontal stand surface, in which
the cleaning station (22) is housed in a lower section (20) and the
finishing station (42) is housed in an upper section (40) lying
vertically above it, wherein the lower and upper sections can be
connected to each other by a passage with a closure (24) which can
be opened, in that a vertical lifting apparatus (44) with a
vertical guide (46) and a holder (48), vertically displaceable
thereon, to which the shaped body (1) can be directly or indirectly
secured, runs through the finishing station in order to be able to
transport the shaped body back and forth between cleaning station
(22) and finishing station (42), in that a control apparatus (4)
integrated into the housing is set up to control the operation of
the lifting apparatus (44), the closure (24) and the cleaning and
finishing stations such that, after the shaped body (1) has been
positioned on the holder and after the closure (24) has been
opened, the lifting apparatus (44) lowers the shaped body into a
basin (26) of the cleaning station (22); to control the operation
of the cleaning station for cleaning the shaped body; after
completion of the operation of the cleaning station (22), to
displace the shaped body (1) upwards into the finishing station
(42) using the lifting apparatus (44); to close the closure (24) of
the passage and then to control the operation of the finishing
station (24) for the post-exposure.
Inventors: |
HENDRIK; John; (Buchs,
CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ivoclar Vivadent AG |
Schaan |
|
LI |
|
|
Family ID: |
61167988 |
Appl. No.: |
16/267510 |
Filed: |
February 5, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 2071/0027 20130101;
B33Y 30/00 20141201; B08B 3/102 20130101; B29C 70/00 20130101; B29C
71/0009 20130101; B29C 73/00 20130101; B29C 2035/0827 20130101;
B29C 64/35 20170801; B33Y 40/00 20141201; B29C 64/379 20170801;
B29C 2035/0833 20130101; B29C 67/00 20130101; B29C 65/00 20130101;
B29C 71/04 20130101; B29C 39/00 20130101 |
International
Class: |
B29C 67/00 20060101
B29C067/00; B33Y 30/00 20060101 B33Y030/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 6, 2018 |
EP |
18155329.8 |
Claims
1. A post processing arrangement for shaped bodies manufactured
additively by photopolymerization comprising a cleaning station for
cleaning a shaped body and a finishing station for post-exposure of
the shaped body, wherein the cleaning station and the finishing
station are housed in a housing (2), configured to stand on a
horizontal stand surface, wherein the cleaning station (22) is
housed in a lower section (20) and the finishing station (42) is
housed in an upper section (40) disposed vertically above the lower
section, wherein the lower and upper sections are connected to each
other by a passage with a closure (24) which can be opened, wherein
a vertical lifting apparatus (44) with a vertical guide (46) and a
holder (48), vertically displaceable thereon, to which the shaped
body (1) can be directly or indirectly secured, extends through the
finishing station in order to be able to transport the shaped body
back and forth between cleaning station (22) and finishing station
(42), wherein a control apparatus (4) integrated into the housing
is configured to control the operation of the lifting apparatus
(44), the closure (24) and the cleaning and finishing stations such
that, after the shaped body (1) has been positioned on the holder
and after the closure (24) has been opened, the lifting apparatus
(44) lowers the shaped body into a basin (26) of the cleaning
station (22); wherein the control apparatus is configured to
control the operation of the cleaning station for cleaning the
shaped body; after completion of the operation of the cleaning
station (22), to displace the shaped body (1) upwards into the
finishing station (42) using the lifting apparatus (44); to close
the closure (24) of the passage and then to control the operation
of the finishing station (24) for the post-exposure.
2. The post processing arrangement according to claim 1, wherein
the lifting apparatus (44) is provided with a rotary drive and the
holder is connected to the rotary drive and designed such that the
shaped body (1) can be set in rotation about a vertical axis by the
rotary drive in order to clean the shaped body by centrifuging of
photopolymerizable liquid.
3. The post processing arrangement according to claim 1, wherein
the cleaning station (22) is provided with a controllable feed for
cleaning liquid and wherein the control apparatus (4) is set up to
control the operation of the cleaning station (22), by filling the
basin (26) with cleaning liquid for cleaning the shaped body
(1).
4. The post processing arrangement according to claim 3, wherein
the lifting apparatus (44) is provided with a rotary drive and the
holder is connected to the rotary drive and designed such that the
shaped body (1) can be set in rotation about a vertical axis by the
rotary drive, and wherein the control apparatus (4) is set up to
set the shaped body in rotation in the cleaning liquid using the
rotary drive after the basin (26) has been filled with cleaning
liquid in order to intensify the cleaning action.
5. The post processing arrangement according to claim 3, wherein
the post processing arrangement is designed for connection of at
least two containers (28) with cleaning liquid and is provided with
a pump (30) and valve apparatuses (32), which, under the control of
the control apparatus (4), selectively pump cleaning liquid from a
container (28) into the basin (6) and, after completion of the
cleaning, out of the basin.
6. The post processing arrangement according to claim 1, wherein
the finishing station (42) is provided with at least two light
sources for post-exposure with different wavelengths.
7. The post processing arrangement according to claim 6, wherein
the finishing station (42) is provided with at least four light
sources for the post-exposure of the shaped body with four
different wavelengths.
8. The post processing arrangement according to claim 7, wherein in
the finishing station (42) the light sources direct light with
maximum wavelengths in the ranges 360-370 nm, 380-390 nm, 400-410
nm and 455-465 nm onto the shaped body.
9. The post processing arrangement according to claim 1, wherein
the control apparatus (4) is connected to an input apparatus for
receiving information about the properties of the shaped body to be
finished and is provided with a memory, wherein in the control
apparatus operating programs for the cleaning station (22) and the
finishing station (42) as a function of information on the
properties of the shaped body are stored, and wherein the control
apparatus is set up to retrieve the associated operating programs
after the information about the properties of the shaped body has
been received, and to control the cleaning station (22) and the
finishing station (42) as required by the retrieved operating
programs.
10. The post processing arrangement according to claim 9, wherein
the input apparatus is a manual input apparatus for the manual
input of information about the properties of the shaped body by a
user.
11. The post processing arrangement according to claim 9, wherein
the input apparatus comprises an automatic reading apparatus which
is designed to read a data storage medium connected to the shaped
body or assigned to it with information on the properties of the
shaped body.
12. The post processing arrangement according to claim 1, wherein
the lifting apparatus (44) and the holder (48) are designed such
that a shaped body (1) is held suspended downwards such that it is
freely accessible to the radiation of the finishing station and the
cleaning liquid of the cleaning station at least from the entire
lower hemisphere.
13. The post processing arrangement according to claim 12, wherein
the lifting apparatus (44) and the holder (48) are designed in
order that a construction platform (6, 8) with the shaped body (1)
adhering thereto can be attached to the holder, wherein the shaped
body is suspended on the construction platform (6, 8) pointing
downwards.
14. The post processing arrangement according to claim 1, wherein
the housing (2) is in the shape of a cylinder or prism.
15. The post processing arrangement according to claim 1, wherein
the upper section (40) of the housing, in which the finishing
station (42) is housed, has an outer wall a flap to be opened,
which allows access, when opened, to the interior of the finishing
station to connect a shaped body to be finished to the holder (48)
of the lifting apparatus (44) and to remove a finished shaped body
from it.
16. The post processing arrangement according to claim 1, wherein
the upper section (40) and the lower section (20) of the housing
(2) are detachably connected to each other.
17. The post processing arrangement according to claim 15, wherein
a bottom wall of the upper section (40) has an opening and a top
wall of the lower section (20) has an opening that is flush with
the opening of the bottom wall in the upper section, wherein the
openings together form the passage and the closure (24) is arranged
at the opening in the top wall of the lower section for the
selective opening and closing of the passage.
18. The post processing arrangement according to claim 16, wherein
the control apparatus is housed in a detachable third section (60)
of the housing, wherein the lower section (20) and the third
section of the housing are designed such that the third section
(60) can be attached to the lower section (20) underneath the lower
section and an electrical connection is disposed between the
control apparatus (4) in the third section (60) and the lower and
upper sections (20, 40).
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to European patent
application No. 18155329.8 filed on Feb. 6, 2018, the disclosure of
which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to a post processing
arrangement for shaped bodies manufactured additively by
photopolymerization which has a cleaning station for cleaning the
shaped body and a finishing station for post-exposure of the shaped
body.
BACKGROUND
[0003] There are now many procedures for manufacturing a shaped
body from liquid, photopolymerizable material using
stereo-lithography-based additive manufacturing (Rapid Prototyping)
by location-selective exposure of successive layers. A layer of
viscous, liquid material is defined on a construction platform and
the layer is polymerized by location-selective exposure by an
exposure unit in an exposure region with a contour predefined for
the respective layer. Then a further layer of photopolymerizable
material is defined on the polymerized layer and this last-defined
layer is polymerized by exposure with a contour predefined for this
last-defined layer. The two last-named steps are repeated until a
shaped body with a predefined shape is formed by the sequence of
cured layers with contours predefined in layers.
[0004] Such a method for manufacturing a shaped body is known for
example from WO 2010/045950 A1, which relates in particular to the
manufacture of dental restorations from liquid, photopolymerizable
materials. In the known method a construction platform is held
vertically movable above a tank bottom which is transparent. There
is an exposure unit underneath the tank bottom. The construction
platform is initially lowered into the photopolymerizable material
until only one layer of photopolymerizable material with the
desired layer thickness remains between the construction platform
and the tank bottom. This layer is then exposed with a predefined
contour by the exposure unit and thereby cured. After the
construction platform has been raised, photopolymerizable material
is newly fed from the surroundings and the construction platform is
lowered again, wherein the lowering is controlled such that the
distance between the last-formed layer and the tank bottom defines
a layer with the desired thickness. Thereafter, the last steps are
repeated until a shaped body with the desired shape is produced by
the sequential curing of layers with in each case a predefined
contour.
[0005] After the polymerization of the last layer, the shaped body
is removed from the manufacturing device by detaching the
construction platform from a holder in the manufacturing device and
removing it with the shaped body adhering thereto. In this phase
the shaped body is still moist, i.e. wetted by liquid,
photopolymerizable material. Furthermore, there can still be areas
in the shaped body with incompletely polymerized material. The
removed shaped body is therefore subjected to post processing for
cleaning and finishing by post-exposure. For this the process is,
for example, as follows in the state of the art, wherein the
preamble of claim 1 relates to such post processing arrangement.
The construction platform with the shaped body suspended thereon is
pushed into a holder frame and this is then dipped into a first
cleaning tank with isopropanol for coarse cleaning. The isopropanol
bath is set in motion by magnetic stirrers in order to detach still
adhering, unpolymerized material from the surface of the shaped
body. After this coarse cleaning, the holder frame is removed from
the cleaning tank and dipped into a second, separate cleaning tank
for fine cleaning. Here too, the cleaning is aided by magnetic
stirrers. Alternatively, ultrasound is also used as actuator, which
is, however, very controversial and not recommended when handling
solvents directly for health and safety reasons. The holder frame
is then raised out of the second cleaning basin, and the shaped
body is subsequently blown with pressurized air in order to remove
the isopropanol with dissolved photopolymer and to dry the shaped
body. Finally, the holder frame with the shaped body suspended
thereon on the construction platform is placed in a separate
finishing device and there subjected to a post-exposure in order to
polymerize still unpolymerized residues in the shaped body. The
handling of the construction platform held in the holder frame with
the shaped body, as well as the transport thereof into and between
the cleaning tanks and to the finishing device, is effected
manually. The setting of the magnetic stirrers, the control of the
cleaning durations in the two cleaning tanks as well as the setting
of the operating parameters of the finishing device are also
likewise effected manually by an operator. The operator must be
protected with gloves in order not to come into contact with the
moist shaped body or the cleaning liquids. Other system providers
recommend removing the shaped bodies from the construction platform
before the cleaning and finishing, wherein the shaped bodies
themselves have to be touched/gripped and handled individually.
This previously described post processing arrangement on the one
hand requires a lot of space (two side-by-side cleaning tanks and a
further post-processing device next to them) and on the other hand
is personnel-intensive as the handling and the transport of the
shaped body held in the holder frame has to be effected manually by
personnel, who also have to set the operating parameters manually
during the cleaning and during the finishing. The post processing
in such a post processing arrangement is therefore
personnel-intensive and error-prone as incorrect settings during
the cleaning and during the finishing can result.
[0006] Besides, there is also already a post processing arrangement
in which the two cleaning tanks are held side-by-side by a frame,
with the result that the two cleaning tanks can be handled as a
unit. However, the problem of the large amount of space required is
not alleviated thereby, since the two tanks are arranged
side-by-side and in this respect occupy a large surface area.
Moreover, the finishing device, as a separate device, also occupies
further space. The problems of the implementing steps of the
finishing being personnel-intensive and the selection and setting
of the correct implementing steps being error-prone are also not
addressed thereby.
[0007] A post processing arrangement for shaped bodies generated by
3D printers is known from US 2016/0107392 A1. In the post
processing arrangement there are a single or several independent
post processing devices. Devices for applying paint or for surface
finishing by abrasives are named as post processing devices. The
post processing device or devices and the 3D printer are connected
to a communication unit which sends the 3D object information for
controlling the 3D printer to the latter and sends post processing
information to the post processing device or devices, which then
automatically carry out the post processing operations on the basis
of this information. In the case of several post processing
devices, the shaped body to be finished is transported manually
between the post processing devices or automatically by an
automatic transport apparatus. The post processing processes of
cleaning by liquid cleaning agent and finishing by post-exposure
are not mentioned in the document.
SUMMARY
[0008] The object of the present invention is to design a post
processing arrangement for shaped bodies manufactured additively by
photopolymerization, which is set up for the post processing steps
of the cleaning of the shaped body in a liquid cleaning agent and
the finishing by post-exposure, such that it has a compact,
space-saving structure and is convenient for the user and can be
operated safely to carry out the post processing.
[0009] The post processing arrangement with the features of claim 1
serves to achieve this object. Advantageous embodiments of the
invention are listed in the dependent claims.
[0010] According to the invention the post processing arrangement
is designed such that the cleaning station and the finishing
station are housed in a housing capable of standing on a horizontal
stand surface, in which housing the cleaning station is located in
a lower section and the finishing station in an upper section lying
vertically above it. The lower and the upper sections are connected
to each other by a passage with a closure which can be opened.
Extending through the finishing station is a vertical lifting
apparatus with a vertical guide and a holder, vertically
displaceable thereon, to which the shaped body can be directly or
indirectly attached in order to be able to transport the shaped
body out of the finishing station into the cleaning station and
back again. A control apparatus integrated into the housing is set
up to control the operation of the lifting apparatus, the closure
and the cleaning and finishing stations such that, after the shaped
body has been positioned on the holder and after the closure has
been opened, the lifting apparatus lowers the shaped body into a
basin of the cleaning station; to control the operation of the
cleaning station for cleaning the shaped body; after completion of
the operation of the cleaning station, to displace the shaped body
upwards into the finishing station using the lifting apparatus; to
close the closure of the passage and then to control the operation
of the finishing station for the post-exposure.
[0011] The integration of the cleaning station and the finishing
station in a relationship such that they lie vertically one above
the other in a housing allows a particularly space-saving and
compact structure. It is particularly advantageous to house the
cleaning station underneath the finishing station lying above it
as, in such a structure, the shaped body can be lowered using the
lifting apparatus from above into the basin, which is open at the
top, in order then to carry out the cleaning steps. After
completion of the cleaning steps, the shaped body is moved by the
control apparatus by operation of the lifting apparatus
automatically upwards into the finishing station, where the control
apparatus then starts and controls the operation of the finishing
station for the post-exposure of the shaped body after the closure
has been closed. The arrangement of cleaning station and finishing
station vertically one above the other in a housing capable of
standing makes it possible to house the post processing arrangement
on a very small footprint, with the result that this can be
installed in a space-saving manner.
[0012] Furthermore, an operator only has to bring the constructed
shaped body into connection with the holder on the lifting
apparatus once, e.g. connect the construction platform with one or
more shaped bodies to the holder, after which the finishing steps
of cleaning and post-exposure proceed automatically under the
control of the control apparatus, with the result that over this
time the operator no longer needs to intervene and no longer comes
into contact with the shaped body, and can thus turn to other tasks
during this time.
[0013] In a preferred embodiment, the lifting apparatus is provided
with a rotary drive. The holder is connected to the rotary drive
and designed such that the shaped body can be set in rotation about
a vertical axis by the rotary drive in order to clean the shaped
body by centrifuging of photopolymerizable liquid. An effective,
contactless removal of residues of photopolymerizable liquid can be
effected by rapid rotation about their own vertical axis. This
cleaning step is effected after the control apparatus has actuated
the lifting apparatus to displace the shaped body on the holder
downwards into the empty basin of the cleaning station, whereupon
the rotary drive is started by the control apparatus in order to
carry out the cleaning step. The centrifuged residues of
photopolymerizable liquid are collected in the basin and therefore
do not lead to contamination of the post processing
arrangement.
[0014] In an alternative preferred embodiment, the cleaning station
is provided with a controllable feed for cleaning liquid. The
control apparatus is set up to control the operation of the
cleaning station, after the shaped body has been lowered into the
basin by the lifting apparatus, by filling the basin with cleaning
liquid for cleaning the shaped body. The cleaning action can be
intensified by magnetic stirrers which are set in rotation on the
bottom of the basin in order to set the cleaning liquid in motion.
Alternatively, the lifting apparatus can be provided with a rotary
drive and the holder can be mounted rotatably on the vertical guide
and connected to the rotary drive, with the result that the shaped
body can be set in rotation by the rotary drive. After the shaped
body has been lowered into the basin with cleaning liquid by the
lifting apparatus, the control apparatus can start the rotary drive
in order thus to set the shaped body in rotation in the cleaning
liquid and thereby intensify the cleaning action.
[0015] In an advantageous embodiment, the post processing
arrangement is designed for connection of at least two containers
with cleaning liquid. For this, for example in the area of the
cleaning station, connection fittings for hoses can be provided
which are connected to containers with cleaning liquid.
Furthermore, in the post processing arrangement, pump and valve
apparatuses are provided which, under the control of the control
apparatus, selectively pump cleaning liquid from a particular
container into the basin of the cleaning station and, after
completion of the cleaning step with this cleaning liquid, pump
this out of the basin, wherein the cleaning liquid is then in most
cases pumped back into the container from which it was removed.
After the cleaning with one cleaning liquid, the control apparatus,
as required by a cleaning program stored therein, by control of the
pump and valve apparatuses, can pump another cleaning liquid from
another selected container with cleaning liquid into the basin of
the cleaning station, carry out a further cleaning step and then
pump the cleaning liquid away again. For example a coarse and then
a fine cleaning can thus be carried out. In order to cause the
cleaning liquid to flow and thereby increase the cleaning action, a
magnetic stirrer or alternatively an ultrasonic actuator is
arranged on the basin bottom.
[0016] In this way it is possible to carry out several cleaning
steps with different cleaning liquids (chemically the cleaning
liquids can have the same basic form, but contain different
proportions of contaminations by photopolymerizable material from
preceding cleaning processes) in a single basin, which requires
much less space than the side-by-side cleaning tanks with the
respective cleaning liquids present in the state of the art.
[0017] In an advantageous embodiment, the finishing station is
provided with at least two light sources for the post-exposure of
the shaped body with different wavelengths, preferably with at
least four light sources for post-exposure with four different
wavelengths. In an advantageous embodiment, the four light sources
are selected such that their maximum wavelengths lie in the ranges
360-370 nm, 380-390 nm, 400-410 nm and 455-465 nm.
[0018] In an advantageous embodiment, the control apparatus is
connected to a input apparatus for receiving information about the
properties of the shaped body to be finished. The control apparatus
furthermore has a memory, in which operating programs for the
cleaning station and the finishing station as a function of
information on the properties of the shaped body are stored. The
control apparatus is set up to retrieve the associated operating
programs for the cleaning station and the finishing station after
the information about the properties of the shaped body has been
received, and to control the cleaning station and the finishing
station as required by the retrieved operating programs. The input
apparatus can be a manual input apparatus on the post processing
arrangement, which is designed for the manual input of information
about the properties of the shaped body by a user. The input
apparatus can comprise, for example, a keyboard or a
touchscreen.
[0019] Alternatively, the input apparatus comprises a reading
apparatus, which is designed to read a data storage medium
connected to the construction platform or the shaped body or
assigned to the latter with information about the properties of the
shaped body. For example, the data storage medium is an RFID
transponder connected to the construction platform, which contains
information about the shaped body manufactured on the construction
platform. The information about the shaped body can comprise its
geometric properties, construction materials used and construction
parameters such as exposure times, etc. Alternatively, the data
storage medium can be a barcode or Data Matrix code, which is
applied to the construction platform or integrated in the shaped
body and which is detected by a reader and transmitted to the post
processing arrangement before the construction platform is
connected to the holder of the lifting apparatus.
[0020] In an advantageous embodiment, the lifting apparatus and its
holder are designed such that a shaped body is held on the holder
such that the shaped body hangs down and is freely accessible from
all sides and from below. In this way, the lifting apparatus can
lower the shaped body into the basin of the cleaning station.
[0021] In a preferred embodiment, the lifting apparatus and its
holder are designed in order that a construction platform with the
shaped body or bodies adhering thereto can be connected to the
holder, with the result that the shaped body is suspended on the
construction platform pointing downwards and is freely accessible
underneath the holder, i.e. there is free access to the shaped
bodies at least over the lower hemisphere underneath the
construction platform for the radiation of the finishing station
and the cleaning liquid of the cleaning station. In this
embodiment, after completion of the construction process on the
construction platform, the shaped body, adhering to the latter, is
removed from the manufacturing device and then inserted, with the
construction platform, into the post processing arrangement.
Inserting the construction platform with the shaped bodies
suspended thereon into the post processing arrangement, without
having to remove the shaped bodies from the construction platform
in preparation for the cleaning and post-exposure, simplifies the
handling during the finishing process. The lifting apparatus can
lower the construction platform towards the basin until the lower
edge area of the construction platform also comes into contact with
cleaning liquid. This has the advantage that the part of the
construction platform which is wetted with uncured
photopolymerizable liquid is also automatically cleaned.
[0022] In a preferred embodiment, the housing unit consisting of
lower and upper sections is cylindrical, preferably in the shape of
a circular cylinder, or prism-shaped.
[0023] In a preferred embodiment, the upper section of the housing,
in which the finishing station is housed, is provided in its outer
wall with a flap that can be opened and closed, and which, once
opened, allows access to the interior of the exposure station for
loading and removing a shaped body to be finished, or a
construction platform including the shaped body.
[0024] In a preferred embodiment, the upper section and the lower
section of the housing unit are detachably connected to each other.
This means that the finishing station in the upper section and the
cleaning station in the lower section can each be formed as modules
which can be connected to each other lying vertically one above the
other and which each have an opening which, in the connected state
of the upper and lower sections, aligned with each other, form the
passage for vertically transporting the shaped body between the
stations, which is attached to the holder or connected to the
holder via the construction platform attached to the holder. The
closure for selectively opening and closing the passage is then
arranged at the opening in the upper wall of the lower section.
[0025] In a preferred embodiment, the control apparatus is housed
in a detachable third section of the housing. The upper and lower
sections, which can be detached from each other, and the third
section of the housing are designed such that the third section
with the control apparatus can be attached to the lower section
underneath the latter. There are electrical connections which
connect the control apparatus to the cleaning station and the
finishing station. The upper section can also be designed such that
the upper section can also be placed on the third housing section
when the upper section is detached from the lower section. In this
embodiment, it is possible in principle to operate the finishing
station and the cleaning station also as separate units, if a
separate operation is advantageous in particular situations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The invention is described below with reference to
embodiment examples in the drawings, in which:
[0027] FIG. 1 shows a schematic cross-sectional view of a finishing
station for the finishing station shown in FIG. 4,
[0028] FIG. 2 shows a schematic cross-sectional view of a finishing
station for the finishing station shown in FIG. 4,
[0029] FIG. 3 shows a schematic cross-sectional view of a cleaning
station for the post processing arrangement shown in FIG. 4,
[0030] FIG. 4 shows a schematic cross-sectional view of an
embodiment of the post processing arrangement,
[0031] FIG. 5 shows a cross-sectional view of the post processing
arrangement shown in FIG. 4, wherein parts that can be detached
from each other have been detached from each other,
[0032] FIG. 6 shows a cross-sectional view of the post processing
arrangement in three different states in the course of a post
processing,
[0033] FIG. 7 shows a schematic cross-sectional view of a further
embodiment of the post processing arrangement, and
[0034] FIG. 8 shows a schematic cross-sectional view of another
embodiment of the post processing arrangement.
DETAILED DESCRIPTION
[0035] In FIGS. 1 and 2, the finishing station 42 is initially, for
explanation purposes, shown detached from the cleaning station of
the post processing arrangement in order to illustrate its
structure and function. The finishing station 42 has a cylindrical
upper housing section 40, in which, close to the upper and the
lower ends, circumferential reflectors 50 are attached which
reflect light in a distributed manner into an exposure region from
light sources arranged distributed around the circumference. Due to
the shape of the reflectors 50, the light is reflected distributed
over a wide range along a central axis. The light beams, reflected
in a distributed manner by the reflectors 50, of the light sources
are indicated in each case by a group of arrows in FIGS. 1 and 2.
Several types of light sources with different maximum emissions can
be distributed around the circumference, with the result that
exposures with desired wavelengths can be carried out.
[0036] On the right in FIG. 1 shaped bodies 1 are represented
schematically, here in the form of dental prosthesis bases, which,
after being manufactured using stereolithography, are still
suspended on a construction platform 6, which has an upper
extension 8 lying opposite the shaped bodies 1. The construction
platform 6 has been removed from a stereolithography device after
completion of the manufacturing process. The construction platform,
with the shaped bodies 1 suspended thereon, is introduced into the
inside of the finishing station 42 through an opening in the outer
wall of the upper section 40 of the housing, which can be opened by
a flap (not shown), as indicated schematically by the arrow in FIG.
1.
[0037] In the finishing station 42 there is a vertical lifting
apparatus 44. This extends through the entire upper housing section
40 with a vertical guide 46, here indicated as a spindle. A holder
48 engages with the vertical guide 46 and can be displaced along
thereon in the vertical direction. The construction platform 6 is
designed, connected to the holder 48, to interact with the vertical
guide 46 in order thus to be displaceable in the vertical direction
by the lifting apparatus 44.
[0038] After the shaped bodies 1 with the construction platform 6
have been placed on the holder and thus on the vertical guide 46,
the exposure of the shaped bodies 1 for their finishing could
already have been carried out, as shown in FIG. 2. In a finishing
station according to the invention, however, after loading of the
finishing station with the construction platform 6 including shaped
bodies 1, the latter is lowered into the cleaning station 22 and
firstly cleaned there, as is described further below.
[0039] The finishing station 42 is provided with schematically
represented fans 50, which dry the shaped bodies, after the
cleaning, by a generated airflow and cool the finishing station 42
during the post-exposure. In addition, the fans guarantee that
solvent vapours are discharged from the finishing station in order
to prevent a possible ignition during the post-exposure.
[0040] FIGS. 1 and 2 show the upper housing section placed on a
third housing section 60, in which a control apparatus 4 for
controlling the different components of the post processing
arrangement is housed. In this configuration, the finishing station
42 can also be operated separately. In FIG. 5, an electrical
connection, which guarantees the connection of the finishing
station to the control apparatus 4 if all modules are arranged one
above the other and connected to each other, is indicated by a
dashed line inside the cleaning station.
[0041] FIG. 3 now shows a cleaning station 22 initially placed in
isolation on the third housing section 60 in order to explain the
structure and function of the cleaning station 22. The cleaning
station 22 is housed in a lower housing section 20, in a top wall
of which there is an opening with a closure 24, which is
represented on the left in FIG. 3 in a top view as an iris valve.
The closure 24 can be opened by the control apparatus 4, after
which the shaped bodies 1 on the construction platform 6, which is
borne by the lifting apparatus 44 through the holder, are lowered
into the cleaning station 22. The construction platform 6 is
designed such that, suspended on the holder 48 of the lifting
apparatus 44, it is lowered, with the shaped bodies 1, into the
cleaning station 22, when the holder 48 is displaced on the
vertical guide 46 downwards into the maximally lowered
position.
[0042] A container or basin 26 which is open at the top is arranged
in the lower housing section 20 in the cleaning station 22. The
cleaning station 22 further comprises a pump 30 and a row of valves
32 connected thereto. External containers 28 with cleaning liquids
can be connected to the valves 32. When the shaped bodies are
located in the interior of the basin 26 lowered into the position
represented in FIG. 3, the pump 30 pumps cleaning liquid from a
selected one of the containers 28, which is selected by opening the
valve 32 assigned to the respective container 28, into the basin
26, which is filled until the shaped bodies 1 and the lower part of
the construction platform dip into the cleaning liquid. The pump 30
and the valves 32 are controlled by the control apparatus 4 in the
third housing section 60.
[0043] The basin 26 is furthermore provided with a magnetic stirrer
25, which sets the cleaning liquid in motion in order to intensify
the process of cleaning the shaped bodies 1 with the cleaning
liquid. As an alternative to the magnetic stirrer, an ultrasonic
actuator can also be arranged on the underside of the basin
bottom.
[0044] After completion of a cleaning step, the pump 30 pumps the
cleaning liquid back out of the basin 26, wherein the cleaning
liquid a generally is pumped back into the container 28 from which
it had previously been pumped into the basin 26. The cleaning
liquid can thereby be re-used. Cleaning liquids of different types
or of different purities can be present in the containers 28, with
the result that successive cleaning steps can be carried out with
different cleaning liquids by pumping in the cleaning liquids
successively from particular containers 28. For example, a coarse
cleaning with a first cleaning liquid from a first of the
containers 28 can be carried out first and, after the cleaning
liquid for the coarse cleaning has been pumped away, a cleaning
liquid of higher purity from another of the containers 28 can be
pumped into the basin in order to carry out a subsequent
cleaning.
[0045] FIGS. 4 and 5 now show the complete post processing
arrangement with the previously described upper housing section 40,
lower housing section 20 and the third housing section 60, wherein
FIG. 5 differs from FIG. 4 merely in that the named housing
sections are represented therein as detachable from each other. In
FIG. 5 an electrical connection, which guarantees the connection of
the finishing station 42 to the control apparatus 4 when all
modules are arranged one above the other, is indicated by a dashed
line inside the cleaning station.
[0046] FIG. 6 shows the post processing arrangement from FIG. 4 in
different states during the finishing. In the left-hand
representation of FIG. 6, the construction platform 6 and the
shaped bodies 1 suspended thereon in the finishing station 42 are
shown suspended on the holder of the vertical lifting apparatus 44,
after the shaped bodies 1 with their construction platform, after
their manufacture in a stereolithography device, have thus been
inserted into the finishing station 42 in the upper housing section
40. The shaped bodies 1 still wetted with photopolymerizable,
uncured material then have to be subjected firstly to a cleaning.
For this, the control apparatus 4 controls the lifting apparatus 44
such that the construction platform 6, placed on the holder, is
displaced downwards. The control apparatus 4 opens the closure 24,
which uncovers an opening of the passage between the upper housing
section 40 and the lower housing section 20, with the result that
the shaped bodies 1, on the construction platform 6, can pass
through the passage into the cleaning station 22 in the lower
housing section 20. When the shaped bodies 1 have been lowered far
enough into the basin 26 of the cleaning station 22, as is shown in
the centre in FIG. 6, the cleaning processes begin through the
pumping-in of cleaning liquids as described above with reference to
FIG. 3.
[0047] After completion of one or more cleaning steps with one or
more cleaning liquids and after the last cleaning liquid has been
pumped out of the basin 26, the control apparatus 4 controls the
lifting apparatus 44 in order to displace the shaped bodies 1
vertically upwards again into the finishing station 42. As soon as
the shaped bodies 1 are again located in the finishing station 42,
the closure 24 can be closed again by the control apparatus 4.
Thereafter, as is shown on the right in FIG. 6, the post-exposure
can then be carried out as described in connection with FIGS. 1 and
2 by the control device 4 operating the desired light sources with
the desired intensity over a desired exposure time in order to
fully polymerize not yet completely cured zones of the shaped
bodies 1. Finally, the construction platform 6 with the shaped
bodies 1 suspended thereon can be removed from the post processing
arrangement by opening the flap (not shown) in the outer wall of
the upper housing section 40 and removing the construction platform
6 with the shaped bodies 1 thereon, thus concluding the finishing
of the shaped bodies 1.
[0048] Between the introduction of the shaped bodies 1 to be
finished into the post processing arrangement and the removal of
the shaped bodies 1 after their finishing, all of the
above-described finishing steps can be carried out automatically
and in a controlled manner by the control apparatus 4, which allows
a stored operating program to be extended. The finishing process is
thereby less personnel-intensive and there are no risks of
individual steps being carried out incorrectly or inadequately by
the personnel, as the steps run according to predefined
programs.
[0049] The embodiment shown in FIG. 7 differs from the previously
described post processing arrangement merely in that in the
embodiment according to FIG. 7 there is further a compressed-air
line 70 which discharges into a plurality of nozzles. The
compressed-air line can be connected to an external compressed-air
source. The control apparatus 4 is set up to guide the shaped
bodies 1 vertically past the nozzles using the lifting apparatus
after completion of the cleaning process in order to blow away
still adhering cleaning liquid by means of compressed air and thus
to improve the cleaning and drying process of the shaped body. In a
preferred embodiment, there can also be only one air nozzle, which
is formed as an airknife, i.e. the nozzle opening is formed as an
elongate nozzle gap. An annular airknife, in which the nozzle gap
is directed annularly onto the inside of the annular airknife, is
particularly preferred. Airflow can thereby be directed from all
sides onto the shaped body moved through the annular opening of the
airknife, in order to free it of residual cleaning liquid and dry
it particularly effectively.
[0050] In a further embodiment, located in the holder for receiving
the construction platform is a rotary drive, which can allow the
construction platform together with shaped bodies to rotate about
the vertical axis in order to remove excess adhering cleaning agent
by centrifugation, instead of by blowing.
[0051] A further embodiment is shown in FIG. 8, in which the
holder, which is vertically displaceable on the vertical guide 46,
is provided with a rotary drive, which can set the construction
platform 6 with the shaped bodies 1 thereon in rotation about the
vertical axis. Through the rotation of the shaped bodies 1 against
the cleaning liquid located in the basin 26 (not shown in FIG. 8),
the cleaning action can be intensified by the movement of the
cleaning liquid in relation to the shaped bodies. In such an
embodiment with a rotatable construction platform, the magnetic
stirrer 25 additionally represented in FIG. 8 is not strictly
necessary. However, as in FIG. 8, it can also be used in
combination with the rotary drive on the holder in order to set the
cleaning liquid in a rotation counter to the rotation of the
construction platform or in order to stop or reverse the rotation
of the cleaning liquid in the basin 26 induced by the rotation of
the construction platform.
[0052] The manner of the cleaning to be carried out and the manner
of the post-exposure to be carried out can depend on properties of
the shaped bodies to be finished. For example, the selection of
both the wavelengths and the intensities of the post-exposure to be
carried out can depend on the size, the shape and the type of
material of the shaped body and on the type of photopolymer which
was used to produce the shaped body. The cleaning steps to be
performed can likewise depend on properties of the shaped body to
be finished in the specific case. For these reasons, the post
processing arrangement is advantageously connected to an input
apparatus for receiving information about the properties of the
shaped body to be finished. The input apparatus can be part of the
post processing arrangement. Furthermore, the control apparatus is
provided with stored operating programs for the cleaning station
and the finishing station and is set up to select, as a function of
the information about the properties of the shaped body to be
post-processed, a stored operating program for the cleaning station
and the finishing station which is suitable for the properties of
the shaped body to be post-processed. The operating program
selected according to the shaped bodies specifically to be
post-processed as determined by the information about its
properties can then run fully automatically in the post processing
arrangement controlled by the control apparatus 4, without the need
for intervention by personnel.
[0053] The input apparatus for the information about the properties
of the shaped body can be a manual input apparatus for the manual
input of the information about the properties of the shaped body by
a user. Alternatively, an automatic reading apparatus can act as
the input apparatus, which is set up to read a data storage medium
connected to the shaped body or assigned to it with the information
on the properties of the shaped body. For example, a data storage
medium in the form of a barcode or a Data Matrix code can be
attached to the upper side of the construction platform 6 facing
away from the shaped bodies 1 or can itself be part of the shaped
body and contain information about the manufactured shaped bodies 1
suspended thereon, which can be read by a code reader as input
apparatus, in order then to use the information on the shaped
bodies 1 for the automatic selection of an operating program
suitable therefore from the memory of the control apparatus 4 and
to allow the selected operating program then to be executed in the
post processing arrangement.
* * * * *